Apparatus for extending the arm of a lever

ABSTRACT

An apparatus for extending the arm of a lever, particularly for extending the arm of a lever of strap tensioning devices, comprising an element for connection to the lever, which can be associated therewith jointly and reversibly, a main body, which is associated with the connecting element by way of elements for mutual inclination and can be gripped by the user to operate the lever, and elements for contrasting the mutual inclination of the main body with respect to the connecting element, which can yield to a predefined force that contrasts the rotation of the lever, applied thereby to the connecting element.

The present invention relates to an apparatus for extending the arm of a lever, particularly for extending the arm of a lever of strap tensioning devices.

BACKGROUND OF THE INVENTION

An apparatus for extending the lever arm is currently known which can be used in particular to tighten the straps for retaining the load on bodies of trucks and the like and has an elongated main body that can be gripped by the user at one end and has, at the other end, an element for connection to a lever whose arm is to be extended.

The connecting element has a box-like structure that is open at one end to accommodate at least part of the lever.

Once the lever has been inserted in such box-like structure, the user, by acting on the main body, actuates the lever, having the benefit of an extended arm which requires him to perform a smaller actuation effort than required for direct actuation of the lever.

Although the use of this apparatus is particularly advantageous, especially when used to operate strap tensioning devices, it has the drawback that the tightening of strap tensioning devices is facilitated so much that it allows to reach the strength limits of the straps and/or of the strap tensioner, causing them to break.

The need is therefore felt for an apparatus for extending the lever arm that allows to limit the tightening force of strap tensioning devices and the like.

SUMMARY OF THE INVENTION

The aim of the present invention is to provide an apparatus for extending the arm of a lever that meets this requirement, allowing to limit the tightening force of strap tensioning devices and the like.

Within this aim, an object of the invention is to provide an apparatus that can be preset to limit the force that can be transmitted thereby to a predefined limit.

Another object of the invention is to provide an apparatus that allows effective tightening of the straps for retaining the load, which is for example arranged on the body of a truck, so as to allow safe transport thereof.

Another object of the invention is to provide an apparatus that is structurally simple and easy to use and can be manufactured with low costs.

This aim and these and other objects, which will become better apparent hereinafter, are achieved by an apparatus for extending the arm of a lever, particularly for extending the arm of a lever of strap tensioning devices, characterized in that it comprises

an element for connection to said lever, which can be associated therewith jointly and reversibly,

a main body, which is associated with said connecting element by way of mutual inclination means and can be gripped by the user to operate said lever by means of said connecting element, and

means for contrasting the mutual inclination of said main body with respect to said connecting element, which can yield to a predefined force that contrasts the rotation of said lever and is applied thereby to said connecting element.

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics and advantages of the invention will become better apparent from the following detailed description of a preferred but not exclusive embodiment of the apparatus according to the invention, illustrated by way of non-limiting example in the accompanying drawings, wherein:

FIG. 1 is a perspective view of an apparatus according to the invention;

FIG. 2 is a sectional view of an apparatus according to the invention, taken along a longitudinal plane;

FIG. 3 is an enlarged-scale sectional view of a detail of the apparatus according to the invention, in the operating configuration.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to the figures, the reference numeral 10 generally designates an apparatus for extending the arm of a lever 11, particularly for extending the arm of a lever 11 of strap tensioning devices, which has the particularity of comprising

an element 12 for connection to the lever 11, which can be associated therewith jointly and reversibly,

a main body 13, which is associated with the connecting element 12 by way of means 14 for mutual inclination and can be gripped by the user to operate the lever 11 by way of the connecting element 12, and

means 15 for contrasting the mutual inclination of the main body 13 with respect to the connecting element 12, which can yield to a predefined force that contrasts the rotation of the lever 11, applied thereby to the connecting element 12.

Advantageously, the inclination means 14 comprise a pivot 16 for coupling the connecting element 12 to the main body 13, for their mutual inclination by rotation about a rotation axis A that is defined by the longitudinal axis of the pivot 16.

The contrast means 15 preferably comprise

a piston 17 that is associated with the main body 13, by way of mutual sliding means, and is provided with a head 18 for pushing against the connecting element 12,

elastic means for pushing the piston 17 along the main body 13 against the connecting element 12.

Further, advantageously, the connecting element 12 is elongated, is associated with the pivot 16 in an intermediate portion thereof, has at one end a region 19 that is equipped so as to lock itself to the lever 11, and has, at the other end, an element 20 for abutment against the head 18.

Conveniently, the main body 13 is box-like, and a cylinder 21 for accommodating such elastic means is formed inside it.

The piston 17 conveniently has, at its opposite end with respect to the head 18, a plate 23, which is inserted slidingly in a first end 22 a of the cylinder 21; at the same time, the head 18 cantilevers out from the first end 22 a.

The main body 13 advantageously has means for contrasting the extraction of the plate 23 from the first end 22 a, which conveniently comprise a stroke limiting shoulder 24 for the plate 23.

Preferably, such elastic means comprise a helical spring 25, which is accommodated within the cylinder 21 and is precompressed between the plate 23 and an end plate 26 that closes a second end 22 b of the cylinder 21.

The head 18 conveniently has a first flat portion 27 for abutment against a corresponding second flat portion 28 formed on the abutment element 20.

Advantageously, the piston 17 and the connecting element 12, when they are associated with the first flat portion 27 that adheres to the second flat portion 28, have the flat portions 27 and 28 arranged substantially transversely with respect to the longitudinal extension of the cylinder 21.

Further, the apparatus 10 preferably comprises means for adjusting the preloading of the spring 25, which conveniently comprise a screw 29 for pushing against the end plate 26 which is screwed onto the bottom 30 of the main body 13, at the first end 22 a.

Preferably, there is also a plug 31 for covering the head of the screw 29, which is associated with the bottom 30.

Use of the apparatus 10 according to the invention is as follows.

The user interlocks the apparatus 10 with the lever 11 at the equipped region 19, then grips the main body 13 and by acting thereon turns the lever 11 about its fulcrum.

The piston 17, pushed by the spring 25 against the connecting element 12, prevents its rotation with respect to the main body 13 gripped by the user, and so the lever 11 is turned thereby jointly with the main body 13.

When the force that contrasts the rotation of the lever 11 is equal to, or greater than, the predefined value preset by the preloading of the spring 25, the spring 25 yields, allowing the rotation of the connecting element 12 with respect to the main body 13.

In this manner, the reaching of the preset limit force for action on the lever 11 is indicated to the user.

In practice it has been shown that the invention achieves the proposed aim and objects, providing an apparatus for extending the arm of a lever that allows to limit the tightening force of strap tensioning devices and the like, such limit force being further presettable by way of the means for adjusting the preloading of the spring.

Further, an apparatus according to the invention, by providing an extended lever arm for strap tensioning devices, allows a more effective tightening of straps for retaining loads, arranged on bodies of trucks or the like, than the fastening that can be obtained by acting directly on the strap tensioning device, so as to ensure safe transport of the load.

The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims; all the details may further be replaced with other technically equivalent elements.

In practice, the materials used, as well as the contingent shapes and dimensions, may be any according to requirements and to the state of the art.

It is noted that anything found to be already known during the patenting process is understood not to be claimed and to be the subject of a disclaimer.

The disclosures in Italian Patent Application No. PD2007A000327 from which this application claims priority are incorporated herein by reference.

Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs. 

1-6. (canceled)
 7. An apparatus for extending the arm of a lever, particularly for extending the arm of a lever of strap tensioning devices, comprising an element for connection to said lever, which can be associated therewith jointly and reversibly, a main body, which is associated with said connecting element by way of means for mutual inclination and can be gripped by the user to operate said lever by way of said connecting element, and means for contrasting the mutual inclination of said main body with respect to said connecting element, which can yield to a predefined force that contrasts the rotation of said lever, applied thereby to said connecting element.
 8. The apparatus according to claim 7, wherein said inclination means comprise a pivot for the connection of said connecting element to said main body, for their mutual inclination by rotation about a rotation axis formed by the longitudinal axis of said pivot.
 9. The apparatus according to claim 8, wherein said contrast means comprise a piston, which is associated with said main body, by way of mutual sliding means, and is provided with a head for pushing against said connecting element, elastic means for pushing said piston along said main body against said connecting element, said connecting element being elongated, associated with said pivot in an intermediate portion thereof and having at one end a region that is equipped to lock itself to said lever, and, at the other end, an element for abutment against said head.
 10. The apparatus according to claim 9, wherein said main body is box-like, a cylinder for accommodating said elastic means being formed inside it, said piston being inserted partially and slidingly in a first end of said cylinder, said main body having means for contrasting the extraction of said piston from said first end, said elastic means comprising a helical spring, which is accommodated in said cylinder and is precompressed between said piston and an end plate that closes a second end of said cylinder.
 11. The apparatus according to claim 10, wherein said head, which cantilevers out from said first end, has a first flat portion for abutment against a corresponding second flat portion formed on said abutment element, said piston and said connecting element, associated with said first flat portion that adheres to said second flat portion, having said first flat portion and said second flat portion arranged substantially transversely with respect to a longitudinal extension of said cylinder.
 12. The apparatus according to claim 10, comprising means for adjusting preloading of said spring. 